The association of mandibular third molar impaction with the dental and periodontal lesions in the adjacent second molars

The Accuracy of Bone Assessment Distal to Lower Second Molars Using Panoramic Radiography: A Systematic Review and Meta-Analysis

Panoramic radiography (OPG) evaluates mandibular third molar impaction (MTMI). This systematic review aimed to investigate the diagnostic accuracy of OPG in detecting bone loss distal to the lower second molars. The associated bone loss with different impaction positions and the most prevalent positions of MTMI were investigated as secondary outcomes. In January 2023, PubMed, Scopus, and Cochrane were searched to identify studies published between January 2012 and January 2023. Two examiners blindly selected the eligible studies for data extraction and quality assessment. Of 427 studies, 8 were suitable for data extraction. All studies reported bone loss distal to the second molar using OPG, ranging from 4.9 to 62.9%. The most frequent position of MTMI is mesioangular. The distal bone loss in the vertical and horizontal positions is statistically significant compared to typically positioned third molars and those that are fully erupted or impacted, but in a normal orientation (p-value 0.005 and 0.02, respectively). Bone loss was not statistically significant in the mesioangular position compared to other impacted positions (p-value 0.14). The risk of bias ranges between 66 and 88%. Despite its limitations, OPG is still considered a valuable tool to assess bone loss distal to the lower second molar in cases of an impacted mandibular third molar.

Mandibular Third Molar Impaction and Bone Change Distal to the Second Molar: A Panoramic Radiographic Study

Background: The mandibular third molar is the most frequently impacted tooth. An impacted mandibular third molar (IMTM) can have negative consequences on the adjacent mandibular second molar (MSM), such as bone loss. An IMTM can be identified using orthopantomography (OPG). Our objective is to compare changes in bone level distal to the mandibular second molar (MSM) in patients with an extracted IMTM versus non-extracted IMTM using OPG. Methods: In this retrospective case-control study, 160 orthopantomograms (OPGs) of 80 patients who attended Dental Hospital of the University of Barcelona (HOUB) were randomly selected. Participants were stratified into a study group and control group. Results: Males and females experienced bone gain in the study group and bone loss in the control group. However, the difference in bone-level change was not statistically significant regarding gender in the study group. Within the study group, the age group of 29-39 years demonstrated significant (p-value = 0.042) bone gain after extraction compared to other age groups. However, the control group demonstrated bone loss in all age groups in which the difference is not statistically significant (p-value 0.794). Conclusions: Bone improvements distal to the MSM were observed after the extraction of an IMTM compared to when an IMTM was not extracted.

The relationship of the position of mandibular third molar impaction with the development of dental and periodontal lesions in adjacent second molars

OBJECTIVE

The aim of this study was to evaluate the effect of different positions of Mandibular third molar impaction teeth on dental and periodontal lesions of mandibular second molars and correlate the lesion severity with patient age.

MATERIALS AND METHODS

This retrospective study assessed 212 CBCT images of patients who visited the department of Oral and Maxillofacial radiology of XX university between 2017 and 2021. Periodontal and dental lesion effects of impacted third molars on mandibular second molars were evaluated. While dental lesions were classified as mild, moderate, and severe, periodontal lesions were classified as mild in cases not exceeding 2/3 of the root, and severe in cases exceeding 2/3 of the root. Pearson's chi-square tests, Mann-Whitney U or Kruskal-Wallis test were used for data analsis. A multivariate logistic regression model was constructed for further analysis.

RESULTS

Periodontal lesions were frequently observed in the second molar adjacent to the third molar (157 teeth, 74.1%), dental lesions were observed in 10%. Among the third molar positions, the mesioangular position was associated with a high (88%) prevalence of periodontal lesions (p<0.001), followed by the horizontal position (71%). The periodontal lesion was more severe in cases 30-39 years old and over 40 years old than in cases under 20 years old and 21-24 years old. Distoangular, horizontal and vertical/inverse positions are less likely to increase the severity of the periodontal lesion than the mesioangular position. (OR = 0.02; p <0.001, OR = 0.28; p =0.008, OR = 0.14; p <0.001,respectively).

CONCLUSIONS

The third molars are often impacted in the mesioangular position, and this position most increases the risk of periodontal infection in the second molars. Accurate diagnosis and evaluation can minimize complications, and CBCT is a reliable imaging technique in which the position of the third molars and their relationship with the 2nd molars can be evaluated.

Effects of modified triangular flap for third molar extraction on distal periodontal health of second molar: A randomized controlled study

Objective

The aim of this study was to assess the effect of flap design for impacted mandibular third molar extraction on the distal periodontal tissue of their neighbors clinically, immunologically, and microbiologically.

Study design

This randomized controlled study comprised 100 patients who were allocated randomly to receive either a triangular flap or a modified triangular flap. The distal periodontal pocket depth, plaque index, bleeding on probing, the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia, and the level of interleukin-1β, interleukin-8 and matrix metalloproteinase-8 of adjacent second molars were measured at baseline, and 1, 4 and 8 weeks after surgery.

Results

After 1 and 4 weeks, distal periodontal conditions of adjacent second molars deteriorated, along with an increase in subgingival microbiota and inflammatory factors in both groups. And compared to the modified triangular flap group, the triangular flap group significantly increased (p < 0.05). Prevotella intermedia, interleukin-1β and probing depth were positively correlated in both groups. After 8 weeks, they returned to the preoperative level.

Conclusions

In this study, both flap designs for impacted mandibular third molar extractions was associated with worse clinical periodontal indices, increased inflammatory biomarkers of gingival crevicular fluid, and more subgingival pathogenic microbiota within 4 weeks. But compared with the triangular flap, the modified triangular flap was better for distal periodontal health of adjacent second molars, which provides certain directions for clinical treatment.

The pattern of mandibular third molar impaction and its relationship with the development of distal caries in adjacent second molars among Emiratis: a retrospective study

Objectives

The purpose of this study was to investigate the pattern of mandibular third molar (MTM) impaction and associated carious lesions in adjacent mandibular second molars (MSMs) in a sample of Emirati individuals.

Methods

This retrospective study assessed 2000 orthopantomograms of Emirati patients who visited the Specialized Fujairah Dental Center between 2015 and 2020. The depth, ramus relation and angulation of the impacted MTMs were assessed according to the Pell and Gregory classification and Winter’s classification. In addition, carious lesions in adjacent MSMs associated with the evaluated parameters were identified.

Results

A total of 461 (23.05%) of the patients had at least one impacted MTM. The mean age of the study population was 26.24 years. Mesioangular, level B, and class II impactions were the most common, at 47.37% (χ² = 382.134; p < 0.001), 45.48% (χ² = 56.889; p < 0.001), and 74.05% (χ² = 513.099; p < 0.001), respectively. There was a higher percentage of level C impaction among females than among males (χ² = 19.178; p < 0.001). A total of 126 impacted teeth (18.36%) had associated carious lesions. These carious lesions were predominantly found in teeth with mesioangular impactions (χ² = 59.430; p < 0.001), level A and B impactions (χ² = 23.301; p < 0.001), and class II and I impactions (χ² = 17.918; p = 0.006).

Conclusions

It is imperative to raise awareness of soft tissue mesioangular-impacted MTMs, as they are the most frequently associated with the development of carious lesions in adjacent MSMs. Approximately one quarter of evaluated Emiratis had at least one impacted MTM, with the most prevalent pattern being class II, level B, and mesioangular impactions. Furthermore, surgical removal is expected to be more challenging for females than for males.

Factors affecting periodontal healing of the adjacent second molar after lower third molar surgery: a systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis aim to evaluate the effect modifiers which may influence the periodontal healing of the adjacent second molar after lower third molar surgery.

MATERIALS AND METHODS

Prospective studies including patients with third molars requiring removal, with at least 6 months follow-up were considered. Outcomes were periodontal probing depth (PPD) reduction, final PPD, clinical attachment level (CAL) change, final CAL, alveolar bone defect (ABD) reduction, and final ABD depth. Meta-regression was performed to identify factors.

RESULTS

Fourteen studies were included in the quantitative synthesis. At 6 months, the PPD reduction was 1.06 mm (95% CI, 0.72 to 1.39 mm) and the remaining PPD was 3.81 mm (95% CI, 3.00 to 4.62 mm). Baseline PPD was strongly correlated with the remaining PPD at 6 months (p < 0.001, adjusted R² = 70.05%).

CONCLUSIONS

Lower third molar surgery results in a modest reduction in PPD, CAL, and ABD; however, periodontal defects still remain at 6 months and beyond. Baseline PPD is strongly correlated with final PPD. While age is not shown to have effect on most of the periodontal parameters, a larger baseline PPD is more likely to manifest with increasing age and third molar surgery should be done before severe periodontitis occurs to avoid persistent periodontal defects.

CLINICAL RELEVANCE

This study shows that lower third molar surgery results in modest improvement in periodontal parameters on adjacent second molars and identified factors such as baseline PPD which may affect the healing, which may guide the pre-, peri-, and post-operative management of lower third molar surgery.

Is it necessary to remove bone-impacted teeth? A retrospective study

BACKGROUND

In clinical practice, it is risky to extract bone-impacted teeth and they're prone to a variety of complications, such as pathological fracture, adjacent tooth fracture, maxillary sinus perforation, and so on, making it difficult for clinicians to decide whether to extract them.

PURPOSE

In order to illustrate our opinions on the possibility of extracting full third molars (M3), 360 examples of complete third molars were analyzed in this study.

MATERIALS AND METHOD

We investigated 2189 patients, and 261 of them provided CBCT images of 360 teeth. assessing the degree of second molar(M2) root absorption in connection to age, impacted relationship, contact part, calculating the odds ratio (OR) and 95% confidence interval using the Logistic regression analysis equation.

RESULT

Bone-impacted M3 occurred in 11.92% (261/2189) of patients with "impacted teeth" diagnoses. There was a significant difference between the occurrence of M2ERR and the contact parts (P value<0.001), and only the type of vertical impaction differed significantly from Level 3 (P < 0.05).

CONCLUSIONS

1) M3 should be removed if root resorption has not occurred in M2. 2) Root resorption is more likely to occur when M3 crown and M2 apical contact. 3) Enough experience, precise preoperative assessment can reduce the dangers to a minimum.

Orthodontic traction of an impacted maxillary third molar through a miniscrew-anchored cantilever spring to substitute the adjacent second molar with severe root resorption

BACKGROUND

An orthodontic traction technique with a miniscrew-anchored cantilever spring was used for the traction of a deeply impacted maxillary third molar to substitute its adjacent second molar with severe root resorption.

CASE DESCRIPTION

A 30-year-old woman sought multidisciplinary treatment planning for a second molar with severe root resorption caused by a deeply impacted third molar. Panoramic radiographs and cone-beam computed tomographic images showed that the third molar was located on the apical and palatal side of the second molar and that the second molar had severe root resorption. The second molar was removed, and the impacted third molar was orthodontically tractioned occlusally with the aid of a miniscrew-anchored cantilever spring. After 12 months of orthodontic treatment, the maxillary left third molar was successfully tractioned occlusally and well aligned with adjacent teeth for the substitution of the second molar. The patient was satisfied with the treatment outcome.

PRACTICAL IMPLICATIONS

A palatal miniscrew-anchored cantilever spring is an effective and viable technique for the orthodontic traction of deeply impacted third molars to substitute second molars with severe root resorption.

Lingual bone thickness in the apical region of the horizontal mandibular third molar: A cross-sectional study in young Japanese

Background

Perforation of the lingual plate in the apical region of mandibular third molars will increase the risk of aberration and migration of the root tip and the risk of lingual nerve injury. The aim of this study was to analyze anatomical information, including relationships between the apical region of horizontally impacted mandibular third molars and lingual plates, in young Japanese.

Methods

Japanese patients, with horizontally impacted third molars, who underwent CT examination as a preoperative assessment for mandibular third molar extraction were included, and anatomical characteristics in the apical region of the right mandibular third molar were analyzed, in this study.

Results

A total of 121 patients were included based on the inclusion and exclusion criteria of this study. The mean and standard deviation of the bone thickness on the lingual side of the mandibular third molar in the apical region was 1.5 ± 1.6 mm, and the absence of lingual cortical bone in the apical region, namely, “perforation”, was observed in 44 patients. The statistical analysis revealed the predictors of cases with perforation as follows: gender, age, and the available space evaluated by Pell and Gregory classification.

Conclusions

This study clarified that “perforation” was sometimes observed in young Japanese, and that the predictors of those cases were as follows: gender, age, and the available space evaluated by Pell and Gregory classification.